Electromagnetically operated latch mechanism



June 26, 1956 R. W. BACH! ET AL ELECTROMAGNETICALLY OPERATED LATCHMECHANISM Filed Feb. ll, 1952 4 Sheets-Sheet l June`26, 1956 R. w. BAcHlET AL ELECTROMAGNETICALLY OPERATED LATCH MECHANISM 4 Sheets-Sheet 2Filed Feb. ll, 1952 Wulf;

Hilf/ /7 ,e0 45 3 ,ai 27 ff Z57162 June 26, 1956 R. w. BACHI ET A1.

ELECTROMAGNETICALLY OPERATED LATCH MECHANISM 4 Sheets-Shee 3 Filed Feb.l1, 1952 June 26, 1956 R. w. BAcHl ET AL 2,752,189

ELECTROMAGNETICALLY OPERATED LATCH MECHANISM o y'ts. Umluft llmlllll 37Robert M .5s/:Z7:

nitecl States Patent O ELECTROMAGNETICALLY OPERATED LATCH MECHANISMRobert W. Bachi, Itasca, and Hardin Y. Fisher, Hillside, Ill.,assignors, by mesne assignments, to Soreng Prod ucts Corporation, acorporation of Delaware Application February 11, 1952, Serial No.270,924 26 Claims. (Cl. 292-336) This invention relates generally tolatch mechanisms and refers more particularly to a latch mechanism whichis especially suited for electromagnetic operation.

It is the general purpose of this invention to provide an improved doorlatch mechanism which can be operated either electromagnetically ormanually in the event of power failure, and featuring a latch bolt whichcan be released manually by relatively simple means entirely iindependently of the means for releasing the latch elec tromagnetically.

Another purpose of this invention resides in the provision of anelectromagnetically operated door latch mechanism incorporating alatching element and a relatively strong spring acting on the latchingelement to hold the same engaged with its keeper under a force greatenough to tightly draw the door closed, and wherein motion of the coremeans for the electromagnet in response to energization thereof isutilized to retract the latching element and load the spring and tocause cooperating parts on relatively movable members of the latchmechanism to be brought into interengaging relationship with one anotherto releasably hold the spring loaded and the latching element in aninoperative keeper releasing position, out of which it must be trippedfor movement to its keeper engaging position by means independent of theelectromagnetic actuator.

It is another purpose of this invention to provide anelectromagnetically operated latch of the character described featuringan energizing circuit for the electromagnet including both a normallyopen switch adapted to be closed manually to complete the energizingcircuit for the electromagnet, and a normally closed switch arranged tobe opened automatically upon release of the latch to effectdeenergization of the electromagnet.

Still another purpose of this invention is to provide a latch mechanismof the character described which is admirably suited for use inrefrigerators, and wherein the interior light of the refrigerator isautomatically energized in consequence of electromagnetic actuation ofthe latch to the keeper releasing position.

With the above and other appear as the description proceeds, thisinvention resides in the novel construction and arrangement of partssubstantially as hereinafter described, and more particularly defined bythe appended claims, it being understood that such changes in theprecise embodiment of the hereinafter disclosed invention may be made ascome within the scope of the claims.

The accompanying drawings illustrate several complete examples of thephysical embodiment of the invention constructed in accordance with thebest modes so far devised for the practical application of theprinciples thereof, and in which:

Figure l is a View partly in side elevation. and partly in verticalsection showing the latch mechanism of this invention embodied in arefrigerator, and illustrating the latch bolt in an operative keeperengaging position;

objects in View, which will pin 30. This pin has its opposite endsFigure 2 is a View similar to Figure l but illustrating the manner inwhich energization of the electromagnet effects release of the latchbolt from its keeper;

Figure 3 is a fragmentary sectional view taken through Figure l alongthe plane of the line 3-3;

Figure 4 is a fragmentary sectional view taken through Figure l alongthe plane of the line 4 4;

Figure S is a front elevational view of the latch mechanism shown inFigure 1 viewed along the line 5 5;

Figure 6 is a fragmentary side elevational view substantiallycorresponding to Figure l but illustrating the manner in which the latchbolt is released from its keeper manually and independently of theelectromagnetic actuating means;

Figure 7 is a wiring diagram illustrating the manner in which both theenergizing circuits for the electromagnet and the interior light of therefrigerator are controlled;

Figure 8 is a side elevational view similar to Figure l but showing aslightly modified embodiment of the invention;

Figure 9 is a side elevational view similar to Figure l but showingstill another embodiment of the invention; and

Figure 10 is a fragmentary detail sectional View shoW- ing a slightlymodified manner of establishing the toggle connection between the latchlever and the movable core means of the electromagnet.

Referring now more particularly to the accompanying drawings in whichlike numerals refer to like parts throughout Ithe several views, thenumeral 10 designates one side wall of a refrigerator having a door 11to close the opening in the front of the refrigerator. The latchmechanism of this invention, generally designated 12, is preferablymounted in the side wall 10 at the front of the refrigerator, oppositethe free upright edge of the refrigerator door 11, and includes alatching element or lever 13 having a bolt 14 thereon engageable with ahook shaped keeper 15 on the rear of the door. An electro` magnetgenerally designated 16 is provided for operating the latch.

A substantially U-shaped mounting bracket 17 is provided for the latchmechanism and the electromagnet 16, the bracket being fixed on the sideWall Il) between the inner and outer side panels 18 and 19 thereof,respectively, and having opposite parallel legs 20 embracing the latchmechanism and the electromagnet. As will be brought out more fullyhereinafter, the latching element or lever 13 is mounted upon thebracket 17 so as to be positioned adjacent to the front edge 22 of theside wall 10 opposite an opening 23 therein to enable the keeper 15 onthe underside of the door to project into the front of the side wall 10for engagement with the latch bolt 14 carried by the lever.

The latch lever 13 comprises a sheet metal stamping having oppositesides 25 held in spaced apart parallel relationship by a strap 26integrally joined thereto. A pivot pin 27 having its ends anchored inthe legs 2t) of the mounting bracket 17 passes through ti e upper endportions of vertically elongated slots 2S in both sides of the latchlever to mount the lever on the bracket for rocking motion about ahorizontal axis.

Though the latch bolt 14 is carried by the latch lever for rockingmotion therewith about the axis of the pivot 27, it is neverthelessmounted on the latch lever for pivotal motion with respect thereto aboutthe axis of a pivot anchored in the sides 25 of the latch lever and isdisposed with its axis parallel to but rearwardly and below the axis ofthe pivot pin 27 for the lever. The rear ends of a pair of opposite arms31 are pivotally received on the pin 3i) and these arms projectforwardly toward the front edge of the'side wall to have the roiler 14which comprises the bolt contined between their forward ends androtatably journaled upon a pin 32 connecting the front ends of the arms.The arms 31, of course, are rigidly joined together as by a cross member33 connecting the 1tower edges of the arms adjacent to the pivot pinSti.

A torsion spring 34 coiied about the pivot pin 30 and having its endsreacting between the latch lever and the arms supporting the latch boltyieldingly urges the latch bolt downwardly toward a normal position withrespect to the lever dened by the engagement of the bottom edges of thearms 31 with inturned llanges 35 on ,the lower edges of the sides 25 ofthe latch lever. The pivotally mounted latch bolt is normally held inthis position, against motion relative to the latch lever, by a manuallyreleasable latching device 57 to be dcscrbed at greater lengthhereinafter.

From the description thus far it will be noted that the latching elementor lever 13 is mounted for pivotal motion about the horizontal axis ofits pivot pin 27 for clockwise rocking motion to carry the latch bolt 14to an operative keeper engaging position suc'n as seen in Figure 1, andfor counterclockwise rocking motion to carry the latch bolt to aninoperative keeper released position such as seen in Figure 2.

The electromagnet is mounted on the bracket 1.7 rearwardly of the latchlever, and includes a coil 4&9 xed to the bracket, and a core comprisinga substantially stationary core element 41 and a movable core element42. Both core elements may be conveniently supported on a common pin 43having its opposite ends anchored in the legs of the mounting bracket sothat the axis of the pin is parallel to that of the lever pivot 27 butis spaced a distance rearwardly and slightly upwardly thereof.

The coil 4) is disposed with its hollow center on a substantiallyvertical artis, and the lower or substantially stationary core element41 extends rearwardly from its supporting pin 43 to lie directlyadjacent to the lower end of the coil. The core element i-1 isyieldingly sup ported in this position by a rubber pad 45 carried by thebight of the bracket 17. The upper or movable core element 42 ispivotally supported by the pin 43 for rocking motion in acounterclockwise direction in response to energization of the coil 4G,to carry an arcuate armature portion 47 thereon into the interior of thecoil from the upper end thereof toward engagement with the portion ofthe stationary core element overlying the underside of the coil.

Response of the pivotally mounted core clement 42 to energization of theelectromagnet is cushioned by the engagement of the pole face 43 on. theupper core elcment with a rubber cushioning pad 49 resting upon the poleface 5t) of the core element 43,; and it will be noted also that theimpact of seating of the upper core element upon the lower core elementis partly borne by the rubber bumper on the mounting bracket.

If desired, the pole pieces of the core elements may have cooperatingtapered surfaces 51 and 52 thereon which pass closely adjacent to oneanother during seating of the upper core member in response toenergization of the electromagnet, to improve the tractioncharacteristics thereof. The surface S1 on the movable core element 42may be defined by a cut-ofi portion at the outer corner of its polepiece, while the surface 52 on the lower core element may comprise aninward extension thereof projecting into the hollow interior of the coiland tapering to mesh with the inclined surface 51 during seating of themovable core element.

The movable core element 42 is yieldingly biased to a retracted positionsuch as seen in Figure 1 defined by its engagement with a rubber bumperS4 carried by the mounting bracket. For this purpose a relatively strongtorsion spring 5S is coiled about the bushing 56 by which t the movablecore element is pivotally mounted upon the pivot pin 43, and the springhas one end 57 reacting against an abutment 58 on the mounting bracketand its opposite end 59 reacting against the movable core elcment 42 toexert a substantial force thereon tending to hold the same swung in aclockwise direction and engaged with the bumper 54.

The movable core clement 42 also has identical arms Gil thereon formedas extensions of the outer laminae thereof. These arms project forwardlyof the pivot pin 43 and have a camming roller 61 received between trerforward extremities, the roller 61 being freely rotatably mounted upon across pin 62 having its opposite ends anchored in the front ends of thearms.

The roller pin 62 is disposed with its aa' parallel to those of thepivot pins 2 7 and 4,3, and mounts the canr ming roller 61 nearlydirectly over the pivot pin 27; so that the roller is carried away fromthe lever pivot during response of the movable core element toenergization of the electromagnet, and toward the lever pivot under theinuence of the strong torsion spring foliowing de-,energi'zation of theelectromagnet.

The arms on the movable core element 42 together with the arm of thelever 13 extending upwardly from its pivot 27 may be considered astoggle linkage, now about to be described, and which linkage has theeicct of making the movable core element 42 a part of the latchmechanism per se. This toggle linkage has interengaging parts thereon,one of which comprises the camming roller 61, and the other of whichcomprises an abutment 64 on the latch lever spaced a distance above thelever pivot and provided by a pin having its opposite ends anchored inthe sides 25 of the latch lever to occupy a position with its axisparallel to those of the pivot pin 27 and the roller pin 62. ln thekeeper engaging position of the bolt seen in Figure l, the abutment 64is engaged with the front of the caming roller 61. substantially on aline with the axis of the roller and that of the pivot 43 for themovable core element 42, and the camming roller thus blockscounterclockwise rocking of the latch lever and bolt to the keeperreleased position.

In this position of the latch lever, therefore, the force of the strongtorsion spring 55 which is utilized to hold the movable core element 42in its retracted position holds the camming roller 61 against the rearside of the abut ment 64 to maintain the latch lever 13 cammed in theclockwise direction about its pivot and in its operative keeper engagingposition. lt will also be noted that in this position of the componentsof the latch, the strong torsion spring 55 is utilized to exert arearward force on the keeper 15, by the latch bolt 1 4, tending to drawthe door 11 toward the front of the refrigerator to hold the seal 66confined therebetween under a degree oi cornpression.

Duringresponse of the movable core clement 42 to energization of theelectromagnet, the core element 42 swings in a counterclockwisedirection about its pivot 43 to carry the camming roller 6i upwardly tothe position` seen'in Figure 2, out of its former position interposedbctween the core clement pivot 43 and the abutment 64 on the latchlever, to free the lever for counterclockwise rockingmotion to thekeeper releasing position shown in Figure 2 and to load the strongtorsion spring 55. in this keeper releasing or inoperative position ofdie latching eiemcnt, the parts 61 and 64 are intercngaged in such amanner that the abutment 64 is interposed between the camming roller 61and the pivot 27 for the latch lever, and a iiat 67 on the upper sido ofthe abutment isV engaged with the underside ot the camming roller toblock clockwise retracting motion of thc movable core element 42 and toreleasably hold the latching element 13 in a cocked keeper releasingposition out of which it must be tripped for return toits operativekeeper engaging position by means independent of the electromagneticactuator.

This cocked position of the latchiug element is dened by' engagement ofthe abutment 64 with a shoulder 68 on each arm 60, beneath the cammingroller, the shoulder being so located that the tangential line ofengagement between the roller 61 and the at on the abutment 64 isdisposed slightly rearwardly of the line joining the axes of the cammingroller and the pivot 27 for the latch lever.

Any suitable means may be provided to impart counterclockwise rocking orcocking movement to the latch lever upon motion of the camming rollerupwardly from behind the abutment 64 on the latch lever, such as linkageor the like connecting the movable core element 42 with the latch lever.An extremely simple manner of effecting such counterclockwise rockingmotion of the latch lever to the inoperative or cocked position residesin the provision of a torsion spring 70 coiled about the latch leverpivot 27 with one end of the spring bearing against a cross pin 71extending between and having its opposite ends anchored to the vlegs 20of the mounting bracket, and passing through an elongatedl slot 72 inthe opposite sides of the latch lever. The opposite end of the torsionspring 70 is extended rearwardly to bear on the upper edge of the strap26 connecting the opposite sides of the latch lever so that the latteris biased to rock in a counterclockwise direction about its pivotwhenever the camming roller 6l is lifted from behind the abutment 64.

It should be noted, however, that the torsion spring 7G is relativelylight and exerts a force on the latch lever, tending to rock the same ina counterclockwise direction, of substantially less magnitude than thatexerted on the latch lever by the heavy torsion spring 55 through theeamming roller 61.

While the keeper released or cocked position of the latch is defined bythe engagement of the abutment 64 thereon with the shoulders 68 on thearms of the movable core element 42, the tripped or keeper engagingposition of the latch is substantially that at which the latch lever hasbeen cammed the maximum distance by the camming roller 61. Consequently,in the tripped position of the latching element the camming roller issubstantially directly interposed between and on a line with theabutment 64 and the pivot 43. Downward over-travel of the arms 6i) tocarry the camming roller farther toward the lever pivot 27, under theinfluence of the torsion spring 55, is limited by engagement of themovable core element 42 with its stop 54.

Attention is directed to the fact that, in the tripped or keeperengaging position of the latch lever, the pro- Jecting ends of thecamming roller pin 62 are received in notches 74 in the upper edges ofthe sides 25 of the latch lever just rearwardly of the abutment 64, butare normally held from contacting the bottom of these notches by therubber stop 54 for the movable core element. However, in the event thelatching element is accidentally tripped while the refrigerator door isopen, so that upon subsequent closure of the door the latch lever mustbe moved bodily upwardly to allow the keeper 15 to engage behind thelatch bolt, the ends of the pins 62 are engaged by the bottoms of thenotches 74 upon initial upward motion of the lever. Such necessaryupward displacement of the latch lever is permitted by the slots 28 and72 in the lever sides, and is imparted thereto by the inclined camsurface 75 on the rear of the pointed upper end of the keeper l duringnal closing motion of the door. By virtue of the engagement of the endsof the pin with the bottoms of the notches 74 continued upwarddisplacement of the latch lever by the keeper rocks the movable coreelement 42 against the force of the strong torsion spring S5. As aresult, .this spring snaps theilatch lever downwardly to engage the boltroller ahead of the keeper as soon as the latter has passed beneath thebolt.

The energizing circuit for the electromagnet is best illustrated inFigure 7 showing a Wiring diagram thereof including the circuit for theinterior light 77 for the refrigerator. As here shown the. power linesand are connected to the opposite ends of the coil 4t) of theelectromagnet through two switches 78 and 79 in series with one anotherin the line L2. The switch 78 is normally open and is adapted to beclosed manually by depression of an actuator 80 on the door of therefrigerator accessible from the exterior thereof. The switch 79 isnormally closed so that manual closure of the switch 78 effectsenergization of the coil 40 of the electromagnet and attraction of thecore element 42 to its seated position, against the force of the togglespring 55.

As explained hereinbefore such energization of the electromagnet andresponse of the core element' 42 effects cocking of the latching elementand release of the latch bolt 14 from its keeper 15, freeing the doorfor opening.

Concomitantly with seating of the core element 42, however', thenormally closed switch 79 in the energizing circuit for theelectromagnet is opened to break the same, and this switch is held openas long as the latching element remains in its cocked position.Consequently, the electromagnet is energized for only the brief periodof time necessary to effect release of the latch bolt from its keeperand engagement of the abutment 64 on the latching element beneath thecamming roller 61 on the core element to releasably hold the latchingelement in its cocked or inoperative position.

The switch 79 is adapted to be opened during seating motion of the coreelement 42 by a part on the latch mechanism which moves therewith duringcocking of the toggle. The structure by which this is accomplished willbe explained shortly.

Also simultaneously with opening of the switch 79 to break theenergizing circuit for the electromagnet a second normally open switch82 is closed, preferably but not necessarily by the same means whichactuates the switch 79 to open the same. Closure of the switch 82completes the energizing circuit for the interior light 77 of therefrigerator so that the same will be illuminated as soon as the toggleis cocked to free the refrigerator door for opening. As shown in Figure7, the light 77 is connected across lines L1 and L2 by a conductor 83having the switch 82 therein.

From this it will be apparent that the electromagnet 16 is energized bymomentary depression of the actuator Si) from the exterior of therefrigerator, and that it will be impossible to effect reenergization ofthe electromagnet once the movable core element thereof has been movedto its seated position to effect full retraction of the latch bolt andcocking of the latching element in its inoperative position by reason ofthe fact that the switch 79 is held in its open position when theabutment 64 on the latching element is engaged under the camming rolleron the core element 42.

When the refrigerator door is reclosed, the latching element is trippedout of its cocked position by a trip linger 85 which, in the presentcase, is separate from the keeper 15 and mounted on the door 11 a slightdistance above the keeper. Because of its proximity to the latch bolt 14when the door is closed, the trip nger is preferably mounted on a pivotpin 86 for upward swinging motion thereon in case it is struck by thebolt during keeper releasing motion thereof. However, the trip nger isyieldingly biased downwardly to an operative position by a relativelylight torsion spring 87 coiled about the pivot pin 86 and reactingbetween the door and a portion of the trip finger forwardly of the pin.

As the door approaches its closed position, therefore, the front of thetrip finger 85 collides with the raised bolt roller 14 and impartsinitial clockwise rocking motion to the latch lever about its pivot 27the distance necessary to carry the abutment 64 on the lever forwardlybeyond the dead center line joining the axis of the camming roller andthat of the pivot pin 27. As soon as the latch lever has been rocked aslight distance clockwise in this manner the strong torsion spring 55acts to cam the lever the remaining distance to its operative positionin which the latch bolt engages a head of the hook-shaped keeper.

The switches referred to in the description of the wiring diagramillustrated in Figure 7 may conveniently be contained in a unitaryhousing 9i) of insulating material mounted in a xed position on theupper front portion of the bracket 17 between the legs thereof, abovethe latch lever. The Switch 78 is contained within the front portion ofthe housing and the switches '79 and 82 are con tained one above theother in the rear portion of the housing and substantially directly overthe camming roller 61.

Each of the switches 79 and 82 has a contactor encircling a push rod 92projecting downwardly out of the housing 9i) with its lower end arrangedto be engaged and lifted by the camming roller 61 during final seatingmotion of the core element 42 to cock the latch mecha nism. Such liftingof the push rod drives the contactors upwardly to eiect opening of thelower normally closed switch 79 and closing of the upper normally openswitch d2. A compression spring 93 acting upon the upper end of the pushrod 92 yieldingly urges the same downwardly to a normal position definedby cooperating shoulders 9d and 95 on the rod and the housing,respectively, in which the switch 79 is closed and the switch 32 isopen.

The switch 78 in the front of the housing is adapted to be closed byrearward depression of a button 97 connecting with the contactor of theswitch and projecting forwardly out of the switch housing. A compressionspring 93 confined between a portion of the housing and the inner end ofthe button 97 yieldingly urges the latter forwardly to hold the switch 78 normally open.

Rearward motion is imparted to the button 97 for the switch 7S by manualdepression of the actuator 8@ from the exterior of the closedrefrigerator door. This motion of the actuator is translated intoclosure of the switch 7S through a cooperating actuator 10i) and a lever101 carried thereby. The actuator 100 is mounted on the upper portion ofthe mounting bracket 17 for sliding motion on an axis aligning with thatof the actuator Si) and projecting forwardly through an opening in thefront 22 of the side wall 1?. The lever 161 extends vertically acrossthe front of the switch housing ahead of the button 97 and its upper endis supported by the actuator 106 which has a reduced rear end portion1tl2 passing loosely through a hole 163 in the upper end of the lever.

Consequently the shoulder 104 at the junction of the actuatorlt) withits reduced rear portion 1552 engages the lever during rearwarddepression of the actuators 3% and 100 to press the upper end portion ofthe lever rearwardly against the button 97 of the switch 7S to eifectclosure of the switch and energization lof the electromagnet.

The rearward motion of the lever lill, of course. is yieldingly resistedby the compression spring 9S and is limited by the engagement of thelever with a convex surface 195 on the front of the switch housing 965.Such engagement of the lever with 'the switch housing also determinesthe extent the actuators 8? and iti@ must be depressed manually toeffect energization of the electromagnet and release of the latchmechanism, since further depression of the actuators is resisted,although not actually prevented, by the engagement of the lever with thefront of the switch housing. Y

in fact, continued depression of the actuators is intended to effectmanual disengagement ofv the latch bolt 14 from a head of the keeper 15,and this is accomplished by exerting a substantial inward force on theactuators 8) and 169 sufcient to rock the lever 191 about the f ulcrumprovided by the convex front of the switch housing to impart forwardswinging motion to the lower end of the lever and release of the latchdevice 37 holding the latch bolt in its normally operative position withrespect to the latch lever.

The latching device 37 comprises a pair of links 163 embracing the frontendsrof the arms 31 and pivotally received on the cross pin 32 of thebolt roller. These linksV project upwardly and their upper ends arerigidll joined by a cross pin 109. The links are also urged to swing inunison in a counterclockwise direction about the pin 32 by torsionsprings 110 coiled about the end portions of the cross pin 32 with theirends connected between the arms 31 and the forward edges of the links108.

The biasing force thus exerted on the links 168 by the torsion springsis utilized to hold the cross pin 169 connecting the upper ends of thelinks engaged in forwardly opening notches 112 in the legs 2t) of themounting bracket. Consequently, with the arrangement described the links108 provide a latch device to hold the latch bolt 14 in its normalposition with respect to the latch lever and out of which it is movable,relative to the lever, by disengagement of the cross pin N9 of the linksfrom its notches 112 and lifting of the links to draw the latch boltupwardly against the bias of the torsion spring acting thereon.

Such disengagement of the cross pin 109 from its notches 112 is eiectedby the lower end of the lever 1M. during forward swinging motion thereofabout the fulcrum provided by the convex front of the switch housing.For this purpose the lower portieri of the lever has a forwardly facinglconvex extremity 114 normally held engaged with the rear side of thecross pin 1'39 by the force of the compression spring 98 for the switch78, and which kicks the cross pin 109 out of its notches upon initialcounterclockwise fulcruming of the lever on lthe front of the switchhousing and thereafter cams the links 108 upwardly to lift the latchbolt from behind the hook-shaped keeper 15.

As .seen in Figure 6 such manual release of the latch bolt entailsupward swinging motion of the arms '31 which carry the bolt roller 14against the for-ce yof the torsion spring 34 acting thereon, and it willbe noted that it is only necessary to raise the bolt roller far enoughto dispose its axis slightly above the pointed upper end of the keeper15 to allow the refrigerator door to be opened by a pull exertedmanually thereon.

it is important to note that the mechanism for effecting manual releaseof the latch bolt operates entirely independently of the electromagneticmeans for releasing the bolt, particularly the movable core element 42of the electromagnet. It is also a feature of this manual bolt releasemechanism that as soon as the actuator 8d is released the latch device37 for the latch bolt is reset automatically. This automatic resettingof the latch device together with return of the latch bolt to its normalposition relative to the latch lever upon which it is mounted iseffected jointly by the springs 98, 34 and 110; these springs rsteffecting rocking of the lever 101 clockwise to its position seen inFigure l, propelling the bolt arms 31 downwardly into engagement withthe flanges 35 on the latch lever to return the bolt to its normalposition with respect thereto, and aligning the cross pin 109 of thelatch device 37 with its notches 112 into which it is then propelled bythe torsion springs 11i?.

The embodiment of the invention illustrated in Figure 8 is substantiallythe same as that hereinbefore described with the exception that the pushrod 92 by which the switches 79 and 82 are controlled is shorter and isactuated by an extension 116 on the latch lever in cooperation with apivoted actuator 117 carried by the mounting bracket beneath the switchhousing 90. For this purpose the actuating lever has a foot 118 thereonengageable with the lower end of the push rod 92', and carries a roller119 in a position to be engaged by a cam surface 120 on the extension116 of the latch lever during cocking of the latch mechanism so that thefinal cocking motion of the latching element swings the actuating leverclockwise to open the switch 79 and to close the switch 82.

In the embodiment of the invention illustrated in Figure 9 the switchhousing 124 is mounted on the upper rear portion of the mounting bracket17' instead of at the front as in the previous embodiments of theinvention.

In this case the cabinet carried actuator 100 has an elongated rearwardextension 125 provided with a cam 126 on its rear extremity to engageand actuate a switch lever 127 to effect closure of the switch 78 andenergization of the electromagnet upon rearward endwise motion of theactuator 100.

The switches 79 and 82 are controlled by a second switch lever 129extending forwardly out of the switch housing and riding upon the outerconvex surface of the armature portion of the movable core element 42'.Hence, the armature normally holds the switch 79 closed and itscompanion switch 82 open in the retracted position thereof. Response ofthe movable core element 42' to energization of the electromagnet,however, carries the curved armature downwardly into the hollow centerof the coil to its seated position, releasing and cocking the latchmechanism. As the armature reaches its seated position, the lever 129drops into a depression 130 on the armature to cause opening of theswitch 79 and deenergization of the electromagnet, and closure of theswitch 82 to complete the energizing circuit for the interior light ofthe refrigerator.

Also in this embodiment of the invention, a transverse fulcrum member132 is provided on the bracket, comlecting the legs thereof; with anouter convex surface 133 thereon to take the place of the convex frontof the switch housing in the previous embodiment of the invention.

ln the embodiment of the invention illustrated in Figure l0, the movablecore element is connected with the latch lever by a pair of links 61rather than the camming roller 61 and abutment 64. These links havetheir opposite ends pivotally received on the pin 62 formerly providedfor the camming roller, and the pin formerly providing the abutment 64on the latch lever; and the links are preferably located adjacent to theinner surfaces of the arms 60 of the movable core element to clear thelower end of the manual release lever 101. The toggle thus provided bythe links 61', however, results in operation of the latch mechanism inthe same manner as described hereinbefore.

From the foregoing description taken together with the accompanyingdrawings, it will be readily apparent that this invention provides anexceptionally reliable electromagnetically operated door latchmechanism, the components of which are connected together toggle fashionwith one of said components comprising a portion of the movable coreelement of the electromagnet itself; and that the energizing circuit forthe electromagnet is automatically broken by a part of the latch itselfin consequence of release and cocking of the latching element.

What we claim as our invention is:

i 1. In a latch of the character described: a latch lever having akeeper engaging latch bolt thereon; pivot means mounting the lever forrocking motion between defined keeper engaging and releasing positions;an electromagnet having a movable core element spring biased to move inone direction but movable in the opposite direction against the biasthereon in response to energization of the electromagnet; a cam on thecore element movable therewith toward and away fromthe latch leverpivot, .response of the core element to energization of theelectromagnet moving the cam away from the latch lever pivot; anabutment on Athe latchlever, spaced from the pivot thereof, and movablewith the lever upon rocking thereof to its keeper releasing positioninto the path of movement of said cam to block spring biased retractingmovement of the core element, said abutment being carried out of thepath of said cam by rocking of the latch lever toward its keeperengaging position to free the core element for spring propelled motionto a retracted position in which the cam engages` the lever abutment toblock rocking motion of the latch lever out of its keeper engagingposition, said cam acting upon the abutment during rocking of the latchlever out of its keeper releasing position to propel the lever to itskeeper engaging position under the force of the spring bias acting uponthe core element; and means rendered effective upon response of the coreelement to energization of the electromagnet for rocking the latch leverto its keeper releasing position.

2. The latch set forth in claim l wherein the latch bolt is pivotallymounted upon the latch lever for movement relative thereto out of akeeper engaging position to enable the latch bolt to be swung to akeeper releasing position independently of the electromagnet; andfurther characterized by the provision of means for releasably holdingthe latch bolt against pivotal motion, relative to the latch lever, outof its keeper engaging position.

3. The latch set forth in claim 1 wherein said means for rocking thelatch lever to its keeper releasing position upon response of the coreelement to energization of the electromagnet comprises a spring actingon the latch lever to yieldingly resist propulsion thereof to its keeperengaging position by the cam on the core element.

4. in a latch of the character described: a latch lever having a keeperengaging latch bolt thereon; pivot means mounting the lever for rockingmotion between defined positions in one of which the latch bolt isengageable with a keeper and in the other of which the latch bolt isreleased from the keeper; an electromagnet having a pivotally mountedcore element which swings in one direction in response to energizationof the electromagnet, against the force of a relatively heavy biasingspring tendino to swing the core element in the opposite directiontoward a retracted position; a cam on the core element movable therewithtoward and away from the latch lever pivot, response of the core elementto energization of the electromagnet moving the cam away from the latchlever pivot; an abutment on the latch lever, spaced from the pivotthereof, and movable with the lever upon rocking thereof to its keeperreleasing position into the path of the movement of said cam to blockspring biased swinging motion of the core element, said abutment beingcarried out of the path of said cam by rocking of the latch lever towardits keeper engaging position to free the core element for springpropelled swinging motion to the retracted position thereof and in whichthe cam engages the lever abutment to block rocking motion of the latchlever out of its keeper engaging position, said earn acting upon theabutment during rocking of the latch lever out of its keeper releasingposition to propel the lever to its keeper engaging position under theforce of the biasing spring acting upon the core element; and meansrendered effective upon response of the core element to energization ofthe electromagnet for moving the latch lever to its keeper releasingposition.

5. The latch set forth in claim 4 wherein the keeper releasing positionof the latch lever is defined by the engagement of cooperating stops onthe latch lever and the core element.

6. r`he latch set forth in claim 4 wherein the keeper releasing positionof the latch lever is defined by the engagement of said abutment on thelatch lever with a shoulder on the core element adjacent to the camthereon.

7. Latching mechanism of the type wherein movement of a latching elementfrom an operative keeper engaging position to an inoperative keeperreleasing position is effected as a consequence of energization of anelectromagnet to cause core means for the electromagnet to move fromretracted to attracted positions: characterized by the fact that saidlatching mechanism comprises two cooperating members movable relative toone another, one of said members comprising a portion of the latchingelement; a connection between the other of said members and the coremeans constraining said other member to move with the core means duringattraction thereof; and cooperating parts on said members brought intointerengagement by movement of the core means to attracted position andthe latching element to its keeper releasing position to releasably holdthe latching element in its inoperative keeper releasing position out ofwhich it may be tripped by moving one of said cooperating membersrelative to the other independently of the electromagnet.

8. in a door latch of the type wherein movement of a door latchingelement from an operative latching position to an inoperative unlatchingposition is effected in consequence of movement of a core element of anelectromagnet from retracted to attracted positions in response toenergization of the electromagnet: arms connected with said elements tomove therewith and interconnected with one another to provide togglelinkage between said elements having a dead center position reachedduring final unlatching motion of the latching element in consequence ofattraction of the core element to cause tte latching' element to bereleasably 'maintained in its unlatching position and the core elementto be releasably held in its attracted position until the toggle linkageis tripped out of its dead center position independently of theelectromagnet, and a relatively strong spring acting on said togglelinkage to effect forceful return of the latching element to itslatching position upon tripping of said toggle linkage out of deadcenter position.

9. The latch set forth in claim 8 wherein the core element of theelectromagnet has an integral portion thereof providing one of saidlinks and wherein said spring acts directly upon the core element toyieldingly hold the same in its retracted position; and furthercharacterized by the provision of a relatively weak spring acting uponthe latching element in a direction to yieldingly resist motion thereofto its operative latching position, said last designated spring beingrendered operative to swing the latching element to its inoperativeunlatching position upon motion of the core element to its attractedposition.

l0. in a, door latching mechanism of the type wherein movement of alatching element from an operative latching position to an inoperativeunlatching position, with respect to a keeper having a bolt engagingsurface facing in the direction of door opening motion, frees tie doorfor opening and is effected by an electro-magnetic operator as aconsequence of motion of core means thereof from a retracted to anattracted position in response to energization of the electromagnet: alatch bolt carried by the latching element for bodily motion therewithto and from engagement with said surface on the keeper; means mountingthe latching element for back and forth motion between its operative andinoperative positions along a path which carries the latch bolt inopposite directions generally corresponding to the directions of dooropening and door closing motion; biasing means forming part of theelectromagnetic operator and operable upon the latching element toforcefully drive the same to its operative position, said biasing meansactin'T upon the latch bolt through the latching element as the latchbolt is carried thereby into engagement with said surface on the keeperto cause the bolt to draw the door tightly closed; and means mountingthe latching bolt on the latching element for movement relative theretoout of its keeper engaging position in a direction substantiallycrosswise of the first designated motion of the bolt.

ll. In door latching mechanism including a latching clement movable backand forth between latching and unlatching positions, and anelectromagnetic actuator including core means movable from retracted toattracted positions in response to energization of the electrornagnet,and wherein movement of the latching element to an unlatching positionis elfected as a consequence of movement of the core means to attractedposition: cooperating parts on the latching element and the core meansbrought into interengagement with one another as a consequence ofattraction of the core means in response to energization of theelectromagnet7 the interengagement of said coi2 operating partsreleasably holding the latching element in its unlatching position outof which it must be tripped by the application of a force theretoindependently of the electromagnet to free the latching element fortravel to its latching position.

12. In an electromagnetically releasable latch mechanism of the typehaving a movable latching element and a latch bolt on the latchingelement carried bodily thereby to and from a keeper releasing position:means for effecting energization of the electromagnet comprising aswitch, and actuating means for the switch including a manually movablemember movable in one direction from one position to another to effectclosure of said switch; means mounting the latch bolt on the latchingelement for motion relative thereto so as to enable the latch bolt to bemoved to another keeper releasing position independently of theelectromagnet; and means for moving the latch bolt relative to thelatching element, to said other keeper releasing position, inconsequence of movement of said manually movable member in saiddirection a distance beyond said other position thereof, said last namedmeans comprising linkage, and means providing a lost motion connectionbetween the linkage, said movable member, and the latch bolt, said lostmotion connection providing for movement of said movable member in saiddirection the distance necessary to effect closure of the switch withoutimparting keeper releasing motion to the latch bolt.

13. In a door latch of the type wherein movement of a latching elementfrom an operative keeper engaging position to an inoperative keeperreleasing position releases a door for opening and is effected as aconsequence of movement of core means of an electromagnet from aretracted to an attracted position in response to energization of theelectromagnet: a loaded biasing spring connected to said core means toyieldingly hold the same in its retracted position and to beadditionally loaded in consequence of response of the core means toenergization of the electromagnet; cooperating parts on the core meansand the latching element brought into interengaging relationship withone another as alconsequence of energization of the electromagnet andrelease of the latching element, to releasably hold the core means inits attracted position and thereby maintain the biasing spring in saidadditionally loaded condition and to releasably hold the latchingelement in its inoperative position, thereby requiring tripping of thelatching element out of its inoperative position, independently of theelectromagnet, to release the core means for retraction; and aconnection between said core means and the latching element renderedeffective upon such tripping of the latching element out of itsinoperative position, through which connection the force of the biasingspring acting upon the core means is applied to the latching element toforcefully propel the latter to and hold it in its operative keeperengaging position.

14. In a latch of the type wherein movement of a latching element froman operative keeper engaging position to an inoperative keeper releasingposition is effected as a consequence of movement of core means of anelectromagnet from retracted to attracted positions in response toenergization of the electromagnet: cooperating parts on said core meansand the latching element which engage one another to block keeperreleasing motion of the latching element when the core means is in itsretracted position, said cooperating parts engaging one another when thecore means is in attracted position and the latching element is in itskeeper releasing position to releasably hold the latching element in itsinoperative Vkeeper releasing position and to block retracting motion ofsaid core means, thereby requiring tripping of said latching element outof its inoperative position independently of the electromagnet to carrythe latching element part-way toward its operative position before thecore means can be retracted.

15. In electromagnetically controlled latch mechanism of the typewherein movement of a latching element from an operative keeper engagingposition to an inoperative keeper releasing position is effected as aconsequence of energization of an electromagnet to carry core means forthe electromagnet from a retracted to an attracted position: a pivotallymounted lever connected with said core means to be driven back and forththereby during attracting and retracting motion of the core means; andcooperating parts on said lever and the latching element which engageone another to block keeper releasing motion of the latching elementwhen the core means is in its retracted position, said cooperating partsengaging one another when the core means is in attracted position andthe latching element is in its keeper releasing position to releasablyhold the latching element in its inoperative keeper releasing positionout of which it may be tripped independently of the core means fortravel to its operative keeper engaging position.

16. In door latch mechanism of the type wherein movernent of a latchingelement from latching to unlatching positions is effected as aconsequence Vof energization of an electromagnet having core meansmovable from retracted to attracted positions in response to suchenergization of the electromagnet: means mounting the latching elementfor swinging motion to and from its latching and unlatcning positions;cooperating cam elements on said core means and the latching element forcamming the latter to its latching position as a consequence ofretraction of the core means, said cam elements engaging one another toreleasably hold the latching element in said unlatching position whenthe core means is in attracted position, and to block retracting motionof the core means, thereby requiring tripping of said latching elementout of its unlatching position before the core means can be retracted;and a spring acting on the core means to yieldingly bias the same towardits retracted position, said spring acting through the cam elements toforcefully propel the latching element to its latching position duringretraction of the core means.

17. Door latch mechanism of the type wherein movement of a latchingelement from a keeper engaging position to a keeper releasing positionis effected as a consequence of movement of core means for anelectromagnet from a retracted to an attracted position in response toenergization of the electromagnet, characterized by: the provision of acam constrained to move back and forth along a xed path and bearingagainst a portion of the latching element to cam the latter to itskeeper engaging position during motion of the cam in one direction to afirst position thereof; a spring connected with the cam for forcefullypropelling the same in said direction to said first position thereof,whereby the spring acts upon the latching element through said cam tofirmly hold the latching element in its keeper engaging position; and amotion transmitting connection between the core means and said cam bywhich the cam is moved in the opposite direction to a second positionthereof at which said spring is loaded, concomitantly with release ofthe latching element, as a consequence of energization of theelectromagnet.

18. The door latch mechanism of claim 17, further characterized by theprovision of means rendered operative by the core means as a consequenceof movement thereof to its attracted position for releasably holding thecam in said second position thereof at which said spring is loaded.

19. In a latch of the type wherein movement of a latching element froman operative keeper engaging position Ato an inoperative keeperreleasing position is effected as a consequence of movement of coremeans of an electromagnet from retracted to attracted positions inresponse to energization of the electromagnet: cooperating parts on saidcore means and the latching element which engage one another to blockkeeper releasing motion of the latching element when the core means isin its retracted position, said cooperating parts engaging one anotherwhen the core means is in attracted position and the latching element isin its keeper releasing position to releasably hold the latching elementin its inoperative keeper releasing position and to block retractingmotion of said core means, thereby requiring tripping of said latchingelement out of its inoperative position independently of theelectromagnet to carry the latching element part-way toward itsoperative position before the core means can be retracted; and springmeans acting upon the core element to yieldingly hold the same in itsretracted position, said spring means acting through said cooperatingparts on the elements during retraction of the core element to effectforceful propulsion of the latching element to its keeper engagingposition.

20. in a door latch of the type wherein movement of a door latchingelement from an operative latching position to an inoperative unlatchingposition is effected in consequence of movement of a core element of anelectromagnet from retracted to attracted positions in response toenergization of the electromagnet: arms connected with said elements tomove therewith and interconnected with one another to provide togglelinkage between said elements having a dead center position reachedduring final unlatching motion of the latching element in consequence ofattraction of the core element to cause the latching element to bereleasably maintained in its unlatching position and the core element tobe releasably held in its attracted position until the toggle linkage istripped out of its dead center position independently of theelectromagnet; a latch bolt mounted on said latching element for bodilymovement therewith between keeper engaging and keeper releasingpositions and for motion relative to the latching element out of keeperengaging position so as to provide for release of the latch bolt in theoperative position of the latching element independently of theelectromagnetic actuator for the latching element; and means forreleasably holding the latch bolt against motion relative to thelatching element, out of the keeper engaging position of the latch bolt.

21.. ln combination with a door for an enclosure: an electromagnet;latching mechanism for the door comprising a latching member movablefrom a latching to an unlatching position to free the door for opening,and a movable core member connected with said latching member andmovable from a retracted position to an attracted position in responseto energization of the electromagnet to effect motion of the latchingmember to its unlatching position; an energizing circuit for saidelectromagnet including a manually operable switch biased to openposition, and a second switch biased to closed position and in serieswith said manually operable switch, said second switch having anactuator; and means mounting said second switch with its actuatoradjacent to the latching mechanism in a position to be actuated by oneof said members so that said second switch is opened thereby and theenergizing circuit for the electromagnet is disrupted as a consequenceof motion of said members to unlatching positions.

22. The combination set forth in claim 21 further characterized by theprovision of cooperating means on said latching and core members whichare brought into interengagement in the unlatching positions of saidmembers to releasably hold said latching mechanism in an unlatchingcondition.

23. The combination set forth in claim 2l wherein said latching memberis mounted for swinging movement between an operative latching positionand an inoperative unlatching position; and wherein said second switchis actuated to open position by said latching member to disrupt theenergizing circuit for the electromagnet upon swinging of the latchingmember to its unlatching position.

24. The combination set forth in claim 2l wherein said second switch isactuated to open position by the core member to disrupt the energizingcircuit for the electromagnet upon travel of the core member to saidattracted position thereof,

25. In a door latching mechanism for the door of an enclosure having aninterior light: a latching member movable from latching to unlatchingpositions to free the door for opening; a movable latch operating memberfor the latching member to effect motion thereof to its unlatchingposition as a consequence of motion of the latch operating member fromone position to another; interengaging means on the latching and latchoperating members cooperable to effect motion of the latching member toits latching position as a consequence of return motion of the latchoperating member to said one position thereof; an energizing circuit forsaid interior light including a normally open switch which must beclosed to complete said circuit; and means on one of said members foractuating said switch to closed position as a consequence of movement ofsaid latch operating member to said other position thereof to effectunlatching motion of the latching member.

26. The door latching mechanism set forth in claim 25 wherein saidinterengaging means on the latching and latch operating memberscooperate to releasably hold the latching member in its unlatchingposition and to releasably hold the latch operating member in said otherposition thereof, whereby said switch is held closed until such time asthe latching member is tripped out of unlatching position.

References Cited in the le of this patent UNITED STATES PATENTS1,325,112 Rodgers Dec. 16, 1919 1,764,784 Freeman June 17, 19301,822,611 Cartia Sept. 8, 1931 2,234,474 Higham et al Mar. 11, 19412,259,136 Hogg Oct. 14, 1941 2,325,225 Burke July 27, 1943 2,359,150Peglow Sept. 26, 1944 2,439,920 Brown Apr. 20, 1948 2,519,197 PrestonAug. 15, 1950 2,550,496 Reischneider Apr. 24, 1951 2,606,052 Soreng eta1. Aug. 5, 1952 2,679,425 Johnson May 25, 1954

